In the bowl of a food processor combine the 3 smashed garlic cloves, prosciutto, crushed red pepper, and 3 cans of beans. Add 1/4 cup olive oil and puree until smooth. If the mixture seems too thick add more olive oil; the mixture should be fairly loose. Taste to see if the mixture needs salt (it probably will). Add the remaining can of beans and pulse to combine (the mixture should be a little bit coarse). Taste again to see if it needs salt. It should be creamy and a little chunky and really well flavored. Remove from the food processor to a large bowl and reserve at room temperature.
Preheat a grill pan over medium heat.
Grill the baguette slices on both sides on the preheated grill pan. When the bread looks slightly charred and is crispy remove them and rub each crostini with the raw garlic cloves.
Top each toast with a big schmear of the bean puree and a drizzle of olive oil. Garnish with sage and arrange on serving platters to serve. Bravissimo!